video: tegra: dsi: modeset notifier

video: tegra: dsi: modeset notifier

* Tweak modeset notifier op to occur before programming
  mode
* On modeset notify, the DSI driver performs Htotal correction
  for ganged mode

Bug 1619492
Bug 1623941

Change-Id: Ie1a134649dd500c4b8a4355528e9cb52136fc20a
Signed-off-by: Daniel Solomon <daniels@nvidia.com>
Reviewed-on: http://git-master/r/717548
(cherry-picked from commit 681024668a874dddf622b317625be1b8464326f2)
Reviewed-on: http://git-master/r/723152
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Mitch Luban <mluban@nvidia.com>